Field of the Invention
The present invention relates to a lens barrel and an optical apparatus having the same.
Description of the Related Art
A lens barrel used for an optical apparatus such as a digital camera or a video camera has a mechanism that moves lens holding members (lens holding frames) holding lens groups in a direction of an optical axis (optical axis direction of an imaging optical system) at the time of, for instance, focusing by means of rotation of a rotary cylinder (cam cylinder).
In this mechanism, the cam cylinder having cam grooves, a guide cylinder (stationary cylinder) having a longitudinal groove (rectilinear groove) parallel to the direction of the optical axis, and cam followers engaged with both types of grooves are used. The cam followers are fixed to the lens holding frames by screws, or the like. As the cam followers move in the direction of the optical axis due to rotation of the cam cylinder, the lens holding frames move in the direction of the optical axis.
To move the lens holding frames along the cam grooves with high precision, it is important to stably fix the cam followers to set positions of the lens holding frames without deviation. To prevent engagement from being released even when the optical apparatus applies an environmental change or shock or when a mass of the lens holding frames increases, an effort to increase a fixing force (e.g., to increase locking quantity) for the lens holding frames of the cam followers is required.
In contrast, Japanese Patent Laid-Open No. H11-305103 discloses a technique for using an energizing force caused by elastic deformation of a member holding cam followers when the cam followers are accurately fixed to a cam cylinder using screws and nuts.
When the locking quantity is increased to improve a fixing force of each cam follower, it is necessary to increase thicknesses of the cam followers or lens holding frames. However, in Japanese Patent Laid-Open No. H11-305103, no description is made of increasing the locking quantity to improve the fixing force.